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Partition calculus on graphs, digraphs and hypergraphs with uncountable chromatic number

Projektbeschreibung

Studie vertieft das Verständnis des Zusammenspiels zwischen endlicher und unendlicher Kombinatorik

Das über die Marie-Skłodowska-Curie-Maßnahmen finanzierte Projekt CHROMPART zielt darauf ab, die Theorie der Partitionsberechnung auf Graphen, Digraphen und Hypergraphen zu erarbeiten, wobei der Schwerpunkt auf den Wechselwirkungen zwischen ein- und mehrdimensionalen Beziehungen liegt. Die Forschenden werden Argumente der Verzweigung zwischen Ergebnissen der Ramsey-Theorie unterschiedlicher Dimensionen untersuchen. Konkret werden sie prüfen, ob Graphen mit nicht abzählbarer chromatischer Zahl notwendigerweise dieselben höherdimensionalen negativen Partitionsbeziehungen erfüllen wie nicht abzählbare vollständige Graphen, und dies mit der Existenz von Orientierungen mit großen dichromatischen Zahlen und Partitionsbeziehungen auf Digraphen in Verbindung bringen. Schließlich werden die Forschenden die Existenz von Oszillationskarten auf dem obligatorischen Hypergraphen erforschen, der mit einem Graphen mit unabzählbarer chromatischer Zahl verbunden ist.

Ziel

Our main goal is to develop the theory of partition calculus on graphs, digraphs and hypergraphs with emphasis on interactions between one-and multi-dimensional relations. Such global characteristics crucially depend on local, often finitary structural properties. This places our project at the meeting point of finite and infinite combinatorics with logic and set theory. Some of the most important questions that motivate our investigations were first raised by P. Erdős and A. Hajnal in the 1960s. Their problems still guide research across finite and infinite combinatorics including the most recent works of R. Diestel, N. Hindman, P. Komjáth, C. Thomassen, S. Todorcevic, and S. Shelah. Our main objective is to investigate ramification arguments between Ramsey-results of varying dimensions. In fact, (1) we study if graphs with uncountable chromatic number necessarily satisfy the same higher-dimensional negative partition relations as uncountable complete graphs. We relate this theme to (2) the existence of orientations with large dichromatic number and partition relations on digraphs. Lastly, we explore a novel concept, (3) the existence of oscillation maps on the obligatory hypergraph associated to a graph with uncountable chromatic number. Our program will be carried out through solving specific, often well-known open problems that are central to these themes. We aim to study both the purely combinatorial and the deep foundational issues that underlie these questions. Hence, we will complement the use of advanced forcing techniques from set theory (such as mixed side-condition methods and new iteration preservation theorems) with novel combinatorial tools, such as minimal walks, oscillation maps and various ZFC construction scheme techniques. We expect our research to produce new methods of wide impact and a significantly deeper understanding of the interactions of finite and infinitary combinatorics.

Koordinator

UNIVERSITY OF EAST ANGLIA
Netto-EU-Beitrag
€ 224 933,76
Adresse
EARLHAM ROAD
NR4 7TJ Norwich
Vereinigtes Königreich

Auf der Karte ansehen

Region
East of England East Anglia Norwich and East Norfolk
Aktivitätstyp
Higher or Secondary Education Establishments
Links
Gesamtkosten
€ 224 933,76